local trade, the constitution of the village and its development by the organization and division of industries, the establishment of communications, the formation of various social groups, and all the processes of commercial and municipal growth into the town and the city. The third book concerns social anatomy and the analysis of the elements and factors in the development described in the preceding book; the fourth book, the physiology and pathology of society; and the fifth book, its psychology. The essay is illustrated by five maps and charts delineating the several stages of the growth of the social organization.
Progress in Flying Machines. By O. Chanute, C. E. The American Engineer and Railroad Journal, 47 Cedar Street, New York. Pp. 308. Price, $2.50.
The subject of aërial navigation has become quite prominent of late by reason of important advances in this field that have been made during the past few years. The idea of controlling the course of a great bag of gas through the currents of the atmosphere has been well-nigh abandoned, and reliance is being placed more and more upon mechanical motors, the buoyancy of the air as exerted under large horizontal surfaces, and the force of the wind. Flying machines are now deemed much more practicable than dirigible balloons. Mr. Chanute's book consists of a series of illustrated articles contributed to The Railroad and Engineering Journal, the chief aims of which were to show whether or not man-flight is possible; to save waste of effort on the part of experimenters by making known what forms of apparatus have failed; and to enable investigators to judge as to whether new machines that may be proposed in future are worthy of trial. The author divides flying machines into three classes: (a) Wings and parachutes; (b) screws to lift and propel; (c) aëroplanes. Flapping wings in imitation of those of birds were early tried, and Mr. Chanute describes many curious forms of them, the earliest authenticated proposal being credited to Leonardo da Vinci. The first known proposal for an aërial screw was also his. Aëroplanes, however, do not date back much before the middle of the present century. Like the first-mentioned class of machines, their principle is derived from an action of birds—in this case the soaring or sailing action. Most of the flying machines described are shown in simple drawings. The results attained by Maxim, Lilienthal, and other recent experimenters are given, the book having been held back from the binder to append Lilienthal's own account of his latest work.
Six General Laws of Nature (a New Idealism) is a compendium, by Solomon J. Silberstein, of a large work which he contemplates publishing, on Divinity and the Cosmos. It is intended to contain "the primitive cause of force and matter, an explanation of all the physical phenomena in the actuality of the universe, and an attack on the modern scientists and philosophers." The author has satisfied himself by careful analysis that all the systems of philosophy are incomplete, unsatisfactory, and insufficient to the deep, logical, and honest thinker, and that most of the laws or axioms in modern natural science are very often defective, and even false. He therefore issues this work in correction of these errors, with the arguments and demonstrations through which he believes he has discovered the mystery and explained the physical phenomena of Nature.
The fields of biology and physics meet in the Investigations on Microscopic Foams and on Protoplasm., by Prof. O. Bütschli, of Heidelberg, which has recently appeared in an English translation (A. & C. Black, London, $6.25). Protoplasm is conceived of in this work as having the structure of a froth or foam in which minute droplets of a watery liquid take the place of air in the bubbles of an ordinary foam. The author has carefully investigated this structure in an effort to throw light upon the physical conditions of the phenomena of life. He has imitated it in oil foams and studied the phenomena of these, and has also investigated the structure of protoplasm in various organisms. About half the work is devoted to a summary of the views of other investigators upon the structure of protoplasm. The volume contains a list of works referred to, an index, twelve lithographic plates, and a number of figures in the text.
In preparing a series of essays on The Relation of Biology to Geological Investigation
